Thank you for your reply. It seems the one thing I chose to try out is too big a mountain to climb for the forseeable future. I will keep at it and try to pick up snippets here and there from other useful threads.

Thanks again for your patience and time.

@zipit

Thank you so much for this Zipit. I hope that I did undertstand some of the points made to an extent. For the purposes of learning, I tried to modify part2 and part3 such that the selected points were only scaling on the local Z for example.

The code works however I had to do silly things - hack transforms of rotation and translation to zero manually to get them to play nice. (*hides). I suspect I am supposed to call direct the 'utils' for positioning directly instead of RotY first then inheriting it and setting transform.off and transform.v3 later.

Utimately, I am trying to get a bunch of polygons (or points in your case) to be coplanar. My idea was to scale them to zero in their local Z axis (the selection's normal not the objects local Z). My current code is working except it is scaling the points to the local objects Z=0 insteal of the axis of the selection's normal .

In my original post. I normally do this via GUI using a custom workplane set to selection whereby I can simple set size in Y to zero. The net effect is the same. ( I know I cannot do this so simply as the coordinate manager cannot be accessed directly)

def part_3():

    transform = c4d.utils.MatrixRotY(math.pi * 0)
    transform.off = c4d.Vector(0, 0, 0)
    transform.v3 *= 0
    points = op.GetAllPoints()

    selection = op.GetPointS()
    state = selection.GetAll(len(points))
    print "selection state:", state

    selected = [i for i, value in enumerate(state) if value]
    print "selected point ids:", selected

    for index in selected:
        points[index] *= transform

    op.SetAllPoints(points)
    op.Message(c4d.MSG_UPDATE)
    c4d.EventAdd()


def main():

    if not isinstance(op, c4d.PolygonObject):
        msg = "Requires a PolygonObject. Received: {type}"
        raise TypeError(msg.format(type=type(op)))


    part_3()

if __name__ == "__main__":
    main()

@SteveLim

I found another thread where the code seems to work except its for World Space and also it affects all points as opposed to selected polys as in my use case.

I tried my luck to modify the code using GetMl instead.. but no dice =)

def set_Y_vector(obj, value):

    oldLocalPoints = obj.GetAllPoints()
    obj_mat = obj.GetMg()
    inv_obj_mat = ~obj_mat

    # Non-preallocation penalty is neglectable 
    newLocalPoints = [] 
    for p in oldLocalPoints:
        # get the world position of the current point
        worldpoint = obj_mat * p
       # set the local position on the new point by setting the y-coordinate to the desired value and transform by the inverted matrix
        newLocalPoint = inv_obj_mat * c4d.Vector(worldpoint[0], value, worldpoint[2] )
        # just append
        newLocalPoints.append(newLocalPoint)

    # set the new points
    obj.SetAllPoints(newLocalPoints)
    
    # notify Cinema 
    obj.Message (c4d.MSG_UPDATE) 
    c4d.EventAdd()

Thank you for replying.

I spent the day looking at your code and other examples. Sad to say it seems I am in quite a bit in over my head.
I was just trying to scale some selected polygons in the Y-Axis... I never knew it would be this complicated.

It is indeed rather disheartening.. are there some beginner examples? I have seen many that try to move selected objects.. but hardly any with selected components + scaling.

Appreciate any small example code.. hopefully I can deduce my way around it.

Hi all,

Just starting out with Python Coding in C4D.

I have watched some tutorials and have basic code that can zero out objects etc.

    objList = doc.GetActiveObjects(True)
    for obj in objList:
        obj.SetRelPos(c4d.Vector(0,0,0))
    c4d.EventAdd()

• I am looking to take the current selection of polygons.

• set the current coordinate manager to world mode

• set the size of them in a particular axis (y) to zero

Thanks in advance for any help you can offer.